New NoRefstateError raised when no refstate output

This allow for simpler types associated with refstate.  The
stagyydata._Refstate class is annotated in this commit.

Author: amorison

stagpy/error.py

@@ -48,6 +48,19 @@ def __init__(self, step: Step):
         super().__init__(f"no geometry info found for {step!r}")
 
 
+class NoRefstateError(StagpyError):
+    """Raised when no refstate output can be found.
+
+    Attributes:
+        sdat: the :class:`~stagpy.stagyydata.StagyyData` instance for which no
+            refstate output was found.
+    """
+
+    def __init__(self, sdat: StagyyData):
+        self.sdat = sdat
+        super().__init__(f"no refstate found for {sdat!r}")
+
+
 class NoParFileError(StagpyError):
     """Raised when no par file can be found.
 

stagpy/refstate.py

@@ -42,8 +42,6 @@ def cmd():
         conf.plot
     """
     sdat = StagyyData()
-    if sdat.refstate.adiabats is None:
-        return
 
     lov = conf.refstate.plot.split(',')
     if not lov:

stagpy/stagyydata.py

@@ -8,16 +8,21 @@
 """
 
 from __future__ import annotations
+from itertools import zip_longest
 import re
 import pathlib
-from itertools import zip_longest
+import typing
 
 import numpy as np
 
 from . import conf, error, parfile, phyvars, stagyyparsers, _helpers, _step
 from ._helpers import CachedReadOnlyProperty as crop
 from .datatypes import Rprof, Tseries, Vart
 
+if typing.TYPE_CHECKING:
+    from typing import Tuple, List
+    from pandas import DataFrame
+
 
 def _as_view_item(obj):
     """Return None or a suitable iterable to build a _StepsView."""
@@ -107,24 +112,26 @@ class _Refstate:
     object.
 
     Args:
-        sdat (:class:`StagyyData`): the StagyyData instance owning the
-            :class:`_Steps` instance.
+        sdat: the StagyyData instance owning the :class:`_Refstate` instance.
     """
 
-    def __init__(self, sdat):
+    def __init__(self, sdat: StagyyData):
         self._sdat = sdat
 
     @crop
-    def _data(self):
+    def _data(self) -> Tuple[List[List[DataFrame]], List[DataFrame]]:
         """Read reference state profile."""
         reffile = self._sdat.filename('refstat.dat')
         if self._sdat.hdf5 and not reffile.is_file():
             # check legacy folder as well
             reffile = self._sdat.filename('refstat.dat', force_legacy=True)
-        return stagyyparsers.refstate(reffile)
+        data = stagyyparsers.refstate(reffile)
+        if data is None:
+            raise error.NoRefstateError(self._sdat)
+        return data
 
     @property
-    def systems(self):
+    def systems(self) -> List[List[DataFrame]]:
         """Reference state profiles of phases.
 
         It is a list of list of :class:`pandas.DataFrame` containing
@@ -139,7 +146,7 @@ def systems(self):
         return self._data[0]
 
     @property
-    def adiabats(self):
+    def adiabats(self) -> List[DataFrame]:
         """Adiabatic reference state profiles.
 
         It is a list of :class:`pandas.DataFrame` containing the reference

stagpy/stagyyparsers.py

@@ -247,7 +247,7 @@ def _clean_names_refstate(names: List[str]) -> List[str]:
 
 def refstate(
     reffile: Path, ncols: int = 8
-) -> Tuple[Optional[List[List[DataFrame]]], Optional[List[DataFrame]]]:
+) -> Optional[Tuple[List[List[DataFrame]], List[DataFrame]]]:
     """Extract reference state profiles.
 
     Args:
@@ -266,7 +266,7 @@ def refstate(
         item being the combined adiabat.
     """
     if not reffile.is_file():
-        return None, None
+        return None
     data = pd.read_csv(reffile, delim_whitespace=True, dtype=str,
                        header=None, names=range(ncols),
                        engine='c', memory_map=True, on_bad_lines='skip')